Industrial truck and tractor battery charger



May 16, 1939. E. w. BRElscH INDUSTRIAL TRUCK AND TRACTOR BATTERY CHARGER 4 Sheets-Sheet 1 Filed April 13, 1936 Edgar W. Bveisch INDUSTRIAL TRUCK AND TR ACTOR BATTERY CHARGER Filed April 13, 1936 4 Sheets-Sheet 2 INSULATION INSULATION Fig".

Edgar W. Breisch attozwp/ y 1 1 E. w. BREISCH 2,158,979

INDUSTRIAL TRUCK AND TRACTOR BATTERY CHARGER Filed April 13, 1936 4 Sheets-Sheet 3 All 16, 1939- E. w. BREISCH 2,158,979

INDUSTRIAL TRUCK AND TRACTOR BATTERY CHARGER Filed April 13, 1936 4 Sheets-Sheet 4 Fig. 9

Edgar W. Bveisch flbtmmw Patented May 16, 1 939 I UNITED STATES PATENT OFFICE INDUSTRIAL TRUCK AND TRACTOR BATTERY CHARGER Edgar W. Breisch, Lancaster, N. Y., assignor to National Battery Company, St. Paul, Minn, a corporaton of Delaware Application April 13, 1936, Serial No. 74,033

8 Claims. (01. 171-314) This invention relates to a battery charger a step by step reduction in the output potential, particularly, although not. exclusively, adapted and for use in charging batteries of industrial trucks Fig. 11 is a diagrammatic illustration of an and tractors, electric street trucks, mine locoalternate form of transformer.

motives, and the like. As best shown in Figs. 1, 2, and 3, I provide It is my object to provide a novel charger of standards Ii and I2, constructed from angle bars unusually inexpensive construction adapted to and rigidly connected together in spaced, parallel efliciently charge batteries of this class. relation by a rear wall I3 and a front wall It.

Another object is to provide a charger of suit- Open mesh screens [5, preferably of the expanded able capacity for such use and of unusually dumetal type are bolted to the frame members H 10 rable construction, the current rectifier being and respectively to Shield t e mechanism and static and other parts subject to a minimum of allow for the admission of cooling air. The top wear. of the cabinet is closed by a suitable plate per- A particular object is to provide a novel charger forated to admit the alternating and direct curadapted to utilize alternating current at the comrent conduits and bolted to the frame members 15 mon commercial voltages and to deliver a direct II and I2 is a front pa el from which the Sevcurrent output of about 75 to 25 amperes at about eral controls, hereinafter described, project. The 28- to 40 volts. cabinet has a floor plate I! and another horizontal A further object is to provide a charger of thi plate i8 divides the interior into a lower comclass having a novel arrangement of transformer, Pertinent containing the rectifier units and a 20 junction rectifier and controls whereby the outmotor-d v n a 20 a d a pp compartment put current may be regulated either manually or containing the transformer and control and timautomatically for maximum efflciency in charging 8 meehahismbatteries of difierent types and in various con- Rlgidly secured to the Walls and a e au ditions of charge. iliary frame members 2| and 22 constructed from 25 Other objects will appear and be more fully angle bars and each consisting of two horizontal pointed out in the following specification and and two vertical angle members welded together claims. into a rectangular structure. A large transform- In the accompanying drawings which illustrate er, in d a ly y th numeral 5 sethe best form of my invention at present known cured t0 the top the members and 22 and 30 to me: has a fixed primary coil 24, an elongated core 25 Figure 1 is a front el t of t charger and a secondary coil 26 movable to and from the cabinet with a portion of th front panel and wall coil 24 along the core 25. The coil 26 is supported broken away to show the rectifier units and coolon a carriage having a Pair of angle members 27 ing fan; connected in spaced parallel relation to each 35 Fig. 2 is a side elevation of the machine with other by similar members 28 (Figs- '3 and the guard screen removed, except a comer Pairs of rollers 29 are mounted on the members tion; 28 to run on tracks 30, these tracks being secured Fig. 3 is a horizgntal section through t to the frame members 2| and 22. A suitable seat inet, showing the interior mechanism in plan; for the 0011 25 S ed Oh t e Carriage mem- 40 Fig. 4 is a fragmentary, vertical section t k bers 21 and the coil is held down by a band havon the line 44 of Fig. 3; 1 ing its ends bolted to the carriage, as best shown Fig. 5 is a section taken on the line 5-5 of in Fig. 5- The bolt 3| for securing One end of Fig. 4, with the guard screen o itt d; the band to the carriage projects beneath the Fig.6isaside elevation of the mercury switches latter and has a Small Compression Spring 3 45 and associated mechanism; mounted thereon to permit expansion and con- Fig. '7 is a front elevation showing the switchtraction of the 0011- operating mechanism, a part of the bracket being Motor-driven means are Provided t0 e the broken away to show parts otherwise concealed; C011 25 Slowly along the e A Screw haft 5 Fig. 8 is a section taken on th li a .a of 33 has suitable journal bearings 34 on the frame Fig. 6, members 2i and 22 respectively and mounted on Fig. 9 is a wiring diagram of the machine, the carriage is a half nut 35 adapted to'engage Fig. 10 is a diagrammatic illustration of the the screw 33. The nut is formed integral with connections for a transformer having one of the an arm 36 which is fixed on a pivot pin 31 integral 5 windings tapped at suitable intervals to provide with a rod 38. As best shown in Fig. 3,the pin 31 has bearings formed in the carriage members 21 and extends at right angles to the rod 38. The free end of this rod has a handle 39 secured thereto in front of the panel I6. A horizontally elongated slot 46 is formed in the panel l6 and a similar slot is formed in the wall l4 to permit movement of the rod 38 with the carriage supporting the transformer coil 26 and also to permit suificient vertical movement of the rod 38 to allow the nut to be moved to and from engagement with the screw 33. Mounted on the panel l6 adjacent to the slot 40 is a scale 4| and fixed on the handle 39 is a.pointer 42 which indicates the position of the coil 26 by reference to the scale 4|.

The screw shaft 33 has secured thereto at one end a sprocket wheel 43 adapted to be driven by a chain 44 and sprocket wheel 45. Suitable gearing in a casing 46 is provided to drive the sprocket wheel and this gearing is driven by a small electric motor 41 mounted on the casing 46.

As shown in Figs. 1 and 2, the rectifier units l9 are mounted in two horizontally spaced, vertical groups, each supported on a rectangular frame 48. These frames are bolted to suitable brackets 49 extending horizontally at the top and bottom and secured to the walls 13 and i4. An electric motor 50 is provided to drive the fan 20 so that the latter creates a partial vacuum in the lower cabinet chamber and efficiently cools the rectifier units, the cooling draft of air being drawn in through one of the screens l5 and between the rectifier units and the warm air being discharged through the opposite screen 15.

Electric switches for controlling the apparatus have handles 5| and 52 mounted respectively on spindles 53 and 54. The spindle 53 is operatively connected to a snap switch 55 arranged, as hereinafter described, in a circuit controlling the timing motor 41. To support the switch 55 and other electrical controls and operating mechanism, a panel 56 of electric insulating material is mounted in spaced parallel relation to the wall I4. The spindle 54 projects through the panel 56 and has pairs of mercury switches 5'! and 58 mounted thereon so that these switches may be simultaneously opened and closed by appropriate rocking movement of the spindle. The switches 51 are arranged to control the alternating current supply circuits and the switches 58 control the direct current output circuit, as shown by the ring diagram, Fig. 9.

As best shown in Figs. 6, 7 and 8, the upper surface of the spindle 54 is flat and has mounted thereon a supporting plate 59 for the switches 51 and 58. A retaining clamp 60 engages the switches 51 and 58 and is held down by small bolts 6| threaded in the spindle 54 and passing between the several switches. Suitable resilient pads are inserted between the supporting plate and tubular bodies of the switches and also be tween the clamp 60 and switches.

A latch and trip mechanism is provided on the front of the panel 56 in connection with the spindle 54. The latch has a channel-shaped bracket 62 bolted to the panel 56 and perforated to afford bearings for the spindle 54. Fixed on the spindle 54 between its bearings in the member 62 is a dog 63, one end of which is adapted to be supported in a notch 64 formed in a lever 65. This lever is pivoted on a bolt 66 projecting from the panel 56 and is urged toward its position indicated in full lines in Fig. 7 by a small spring 51. One end of this spring is secured to the lever and the other end to a rigid support 68 depending from the bracket 62. Another spring 69 is attached to the support 68 and to the dog 63 to urge said dog toward the position indicated in dotted lines in'Fig. 7. The lever 65 has an inwardly offset end 18 which projects into the path of a rigid trip member H mounted on the carriage supporting the transformer coil 26. It will be understood that the switches 51 and 58 are so positioned on the spindle 54 that they are in their closed position when the handle 52 of the trip mechanism is turned in a clockwise direction. Upon movement of the lever 65 to the dotted line position (Fig. '7), the dog 63 is released from the notch 64 and the spring 68 tilts the switches to their open position. The trip member II is so located on the transformer carriage that it strikes the lever 65 to open the switches as the carriage approaches the end of its movement to the right, as seen in Figs. 1 and 3. An ammeter T2 is mounted near the top of the panel [6 and this meter is connected in the direct current output circuit, as shown in Fig. 9. As further indicated by the wiring diagram, an alternating current supply is indicated by the wires 13 and 14 and the primary coil 24 of the transformer is placed in series with the switches 5'! in the supply circuit. One branch of this circuit includes the fan motor 56 and wires l5, l6 and 11. A second branch of the alternating current circuit comprises a wire 18, the motor 47, wire 19, switch 55 and wire 80, connected to wire 15.

The secondary coil 26 is included in an entirely separate, direct current circuit including the rectifier units l9, wires 8| and 82 severally connecting the banks of rectifying units to the secondary coil, wire 83 extending to a shunt 84 for ammeter 12 and wire 85. A second output circuit wire 86 extends to branch circuits including the switches 58in parallel with each other. A wire 81 connects these circuits to the output side of one rectifier group. As indicated, the rectifier units are arranged in balanced groups and are preferably of the copper oxide type, al-

though other junction rectifiers may be employed. Suitable fuses are placed in the alternating and direct current circuits, as indicated in Fig. 9, and these fuses are preferably mounted on the panel 56.

As shown in Fig. 10 a transformer having one,

a multiplicity of taps 89 which are successively contacted by a movable contact member 90. The output circuit wire 82 is connected to the member 90 andthewire 8| to one end of the winding 88. The member 90 is moved at such rate that it will travel from the extreme left to the extreme right tap during a period of ten hours and a sufficient number of the taps 89 are provided to reduce the output potential step by step at intervals of one hour. The member 90 remains in contact with each tap for a period of one hour. The member 90 may be actuated by a screw-threaded shaft, such as the shaft 33, so that the moving member 96 completes the circuit through each of the successive taps 89 for a predetermined period of time. The change from one position to another should be made without appreciable loss of time and where the transformer is of the type with good regulation, the necessary current control may be secured by placing a reactor Si in the output circuit, as illustrated in Fig. 10, or in the transformer.

input circuit including the primary winding of the transformer. Suitable mechanism for making the successive contacts with the taps I9 is well known in this art. For example, the movable nut on the shaft 33 may actuate overcenter contactors or snap switches so constructed that they snap to either open or closed position with a quick movement as they pass a dead center position and being spring actuated to open position except when held closed by the motor or clock operated mechanism.

Operation My improved charger may be operated in different ways to efficiently charge batteries of various types and in various conditions of charge. Where the battery is of the lead-acid type and is to be recharged from a substantially discharged condition, best results are obtained by starting with the maximum rate of charge and gradually reducing this during a period of about ten hours, the final charging rate being equal to about onehalf of the maximum.

Where, as in many vehicles, the battery contains fourteen to sixteen cells of the lead-acid type an initial charging rate of 65 to 75 amperes at approximately 28 volts is required and this should be gradually reduced to approximately amperes at 40 volts at the end of the charging period. My charger is particularly adapted to fulfill such requirements. To operate my improved charger under the normal conditions with a leadacid battery, the battery is connected to the output circuit wires 85 and 86, the snap switch 55 is closed by appropriate movement of the handle 5| and the switches 51 and 58 are closed by turning the handle 52 of the spindle 54 to the right as seen in Figs. 1 and 7. Turning the spindle 54 to the right forces the dog 63 into the notch 64 against the action of the springs 61 and 39 and moves the switches 51 and 58 to the closed position indicated in Fig. 8. The switches will remain in this closed position until the lever 65 is actuated to release the dog 63 from the notch 64. When the operation is to start with the maximum rate of charging, the handle 39 is manipulated to move the secondary coil 26, together with its carriage, to the extreme left as seen in Figs. 1 and 3, so that there is a minimum of leakage between the primary and secondary coils of the When the handle 39 is released the nut engages the screw shaft 33. The tim ing motor 41 and fan motor 50 operate when the switches 55 and 51 are closed so that, under the conditions stated, the timing motor slowly turns the screw shaft 33 through the speed reducing gears, chain M and sprocket wheels 43 and 45. The rate of turning the shaft 33 is preferably such that the secondary coil 26 is moved from its maximum to its minimum charging position during a period of about ten hours, Throughout this period the direct current output is gradually reduced. This charges the battery in a minimum of time while avoiding damage such as is caused by too rapid charging, with resulting excessive gassing, overheating, etc. At the end of the predetermined charging period, the contact member II on the transformer carriage actuates the lever 65 to release the dog 83 from the notch 64. This automatically opens the switches 51 and 58 controlling the alternating and direct current circuits respectively.

My machine is also adapted to efficiently recharge a battery requiring less than a full charge, or one which has not been completely discharged.

By a simple test the percentage of charge re--' maining in such a battery may be determined. The corresponding position for the handle 99 and initial rate of charging is indicated on the scale 4!. where, for example, a battery contains 50% of its full charge, the recharging is started with the pointer 42 on handle 39 at the corresponding point on the scale 4|. Such a battery is efficiently recharged and the current supply automatically cut off at the end of the proper period of charging.

Another method of operation is required for nickel-alkaline batteries such as Edison batteries. To charge such batteries, the timing motor control switch 55 is moved to the open position by suitable manipulation of the handle 5i and the handle 39 is set at such position relative to the scale 4| and by reference to the ammeter 12 as to give the rate of charging desired within the capacity of the apparatus. It will be understood that with the timing motor out of operation the rate of charging is constant for any position of the handle 39 and may be changed from time to time, as desired, by suitable manipulation of the handle 39. What is termed a boosting charge may be given the battery by setting the control handle 39 for the maximum charging rate and allowing the charging to con tinue for a short period of time. Other methods of operation known as triple and double rate charging may also be utilized with my improved apparatus.

I have found that for charging batteries of 14 to 16 cells the transformer should produce in the secondary coil a maximum alternating current I voltage of about '75 volts. This is reduced to about volts D. C. by the rectifier and the maximum direct current output equals about 75 to 65 amperes; depending upon the alternating current input rating. For other types of vehicles, such as mine locomotives and electric street trucks, a maximum charging rate of about 100 amperes at a voltage of not less than 120 volts is required. My improved charger is adapted to meet these requirements and even considerably higher output current and voltage requirements.

A number of modifications in the preferred details will be obvious to those skilled in this art. For example, in place of the moving coil transformer, a tapped transformer with voltage reductions made periodically, such as one each hour, throughout the charging period, as illustrated and described herein with reference to Fig. 10 of the drawings, is considered to be within the spirit of the invention. The timing or progressive reduction of the secondary voltage may also be accomplished by the use of a synchronous motor or clock operated timing mechanism. For obvious reasons, including that of safety, it is preferable to have the direct current circuits entirely separated from the power supply circuits. However, where the current supply voltage is low, or does not greatly exceed about 115 volts, an auto or single winding transformer such as that shown in Fig. 11 may be used in place of the double winding transformer illustrated and described in detail here n. Windings 92 of this auto-transformer may be moved relative to the windings 93 to progressively duce the output potential or windings 92 may be tapped as illustrated and described with reference to Fig. 10.

Having described my invention, What I claim as new and desire to protect by Letters Patent is:

1. An industrial truck and tractor battery charger comprising, a transformer having relatively movable primary and secondary windings, a. junction rectifier, a circuit for supplying alternating current to said primary winding, a control switch included in said circuit, a second circuit including the secondary Winding of said transformer and said rectifier, a multiplicity of batteries, a direct current output circuit from said rectifier including said batteries, means for slowly moving one of said windings relative to the other during an extended period of time and means for the actuating said switch at the end of said period.

2. An industrial truck and tractor battery charger comprising, a transformer having relatively movable primary and secondary windings, a junction rectifier, a circuit for supplying alternating current to said primary winding, a second circuit including the secondary winding of said transformer and said rectifier, a thirdcircuit for the direct current output from said rectifier, a multiplicity of batteries to be charged included in said third circuit, an electric motor, means operable by said motor for moving one of said windings relative to the other, a branch of said first mentioned circuit including said motor in parallel to said primary winding, a switch controlling said first mentioned and branch circuits and means operable by said motor for automatically opening I said switch.

3. An industrial truck and tractor battery charger comprising, a transformer having relatively movable primary and secondary windings, a junction rectifier, a circuit for supplying alternating current to said primary winding, a second circuit including the secondary winding of said transformer and said rectifier, a third circuit for the direct current output from said rectifier, a multiplicity of batteries to be charged in cluded in said third circuitjan electric motor, means operable by said motor for moving one of said windings relative to the other, a branch of one of said first mentioned circuits including said motor, switches arranged to control said first mentioned, third and branch circuits and means operable by said motor, for actuating said switches.

4. An industrial truck and tractor battery charger comprising, a transformer having relatively movable primary and secondary windings, a copper oxide rectifier, timing and fan motors, a circuit for supplying alternating current to said primary winding, branches of said circuit respectively including said timing and fan motors, a second circuit including the secondary winding of said transformer and said rectifier, a third circuit for the direct current output from said rectifier, a multiplicity of batteries to be charged included in said third circuit, a fan operable by said fan motor and arranged to cool said rectifier, means operable by said timing motor for moving one of said windings relative to the other, switches for controlling said first-mentioned, third and branch circuits and means operable by said timing motor for automatically opening said switches.

5. An industrial truck and tractor battery charger comprising, a transformer having primary and secondary windings and a movable member for varying the inductance thereof, a junction rectifier, a circuit for supplying alternating current to said primary winding, a. control switch included in said circuit, a second circuit including the secondary winding of said transformer and said rectifier, a multiplicity of batteries, a direct current output circuit from said rectifier including said batteries, means for slowly moving said transformer member during an extended period of time to progressively reduce the output potential therefrom and means for actuating said switch at the endof said period.

6. An industrial truck and tractor battery charger comprising, a transformer of variable inductance type having primary and secondary windings, a junction rectifier, a circuit for supplying alternating current to said primary winding, a control switch, a second circuit including the secondary winding of said transformer and said rectifier, a multiplicity of batteries, a direct current output circuit from said rectifier including said batteries, movable means for varying the inductance of said transformer to regulate the output potential therefrom, means for slowly actuating said movable means during an extended period of time and means for actuating said switch at the end of said period.

'7, In a battery charger of the class described, a transformer having primary and secondary windings and a member movable to regulate the inductance thereof, a junction rectifier, a circuit for supplying alternating current to said primary winding, a control switch included in said circuit, I

a second circuit including the secondary winding of said transformer and said rectifier, a direct current output circuit from said rectifier for the batteries to be charged, an electric motor operatively connected to said movable member for progressively reducing the output potential from said rectifier during an extended period of time, manually operable means for setting said movable member to determine the initial charging rate and duration of the charging period and means operable by said motor for actuating said switch to open position at the end of said period.

8. In a battery charger of the class described, a transformer having primary and secondary windings and a member movable to regulate the inductance thereof, a junction rectifier, a circuit for supplying alternating current to said primary winding, a second circuitincluding the secondary winding of said transformer and said rectifier, a direct current output circuit from said rectifier, batteries to be charged included in said output circuit, a switch controlling said output circuit, a motor operatively connected to said movable member for progressively varying the output potential from said rectifier during an extended period of time, manually operable means for setting said movable member to determine the initial charging rate and means operable by said motor for actuating said switch to open position at the end of said period.

EDGAR W. BREISCH. 

